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ORCID
https://orcid.org/0000-0002-4152-6813
Access Type
Open Access Thesis
Document Type
thesis
Degree Program
Geosciences
Degree Type
Master of Science (M.S.)
Year Degree Awarded
2022
Month Degree Awarded
May
Abstract
Soil erosion undermines agricultural productivity, limiting the lifespan of civilizations. For agriculture to be sustainable, soil erosion rates must be low enough to maintain fertile soil, as was present in many agricultural landscapes prior to the initiation of farming. However, there have been few measurements of long-term pre-agricultural erosion rates in major agricultural landscapes. We quantified geological erosion rates in the Midwestern U.S., one of the world’s most productive agricultural areas. We sampled soil profiles from 14 native prairies and measured concentrations of the cosmogenic nuclide 10Be and chemically immobile elements to calculate physical erosion rates. We used the erosion rates and measurements of topographic curvature to estimate a pre- agricultural topographic diffusion coefficient. We find pre-agricultural erosion rates of 0.0001–0.1 mm yr-1 and a site-averaged diffusion coefficient of 0.005 m2 yr-1. The pre- agricultural erosion rates and diffusion coefficient we measured are both orders of magnitude lower than anthropogenic values previously measured in adjacent agricultural fields. The pre-agricultural erosion rates are one to four orders of magnitude lower than the 1 mm yr-1 soil loss tolerance value assigned to these locations by the U.S. Department of Agriculture. Hence, as currently defined, tolerable soil loss will lead to unsustainable erosion of Midwestern soils. However, quantifying natural erosion rates via cosmogenic nuclides provides a means for more robustly defining rates of tolerable soil loss and developing management guidelines that promote soil sustainability.
DOI
https://doi.org/10.7275/28631952
First Advisor
Isaac Larsen
Second Advisor
Marco Keiluweit
Third Advisor
Matthew Winnick
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Lauth Quarrier, Caroline, "Pre-agricultural Soil Erosion Rates in the Midwestern U.S." (2022). Masters Theses. 1195.
https://doi.org/10.7275/28631952
https://scholarworks.umass.edu/masters_theses_2/1195